High performance two-port transport LAN bridge

Abstract

A transparent bridge between a pair of local area networks is comprised of a database for storing destination addresses for frames of data, a pair of frame transfer agents each connected to the database for transferring frames of data in respectively opposite directions from one LAN to the other depending on whether addresses stored in the database correspond to destination addresses of the frames of data.

I claim: 
     
       1. A transparent bridge between a pair of local area networks (LANs) each being associated with a MAC, comprising: (a) a pair of frame transfer agents connected in parallel between the LANs each for receiving frames of data and frames of messages from corresponding MACs, each frame transfer agent for discriminating between said frames of data and frames of received messages, for transferring frames of data in only one direction opposite from the other frame transfer agent of the pair from a corresponding MAC to the other MAC and being devoid of microprocessor,   (b) a local manager connected to each frame transfer agent for receiving said received messages and for processing said received messages received from either of the MACs, and for generating further messages for each MAC,   (c) a filtering database connected to each frame transfer agent for storing a static destination address of said local manager of said received messages received from one of the MACs, and for storing dynamic destination LAN addresses for frames of data, and   (d) each frame transfer agent containing means for accessing the filter database to determine whether the frames of data received by the transfer agent are transferable to said other MAC, depending on a destination address of said other MAC, and to determine whether the frames of said received messages are transferable to the local manager for processing, depending on a destination address of said local manager.   
     
     
       2. A bridge as defined in claim 1, in which the data addresses stored in the filter database each contains bits designating whether frames bearing an address of one of the MACs are forwardable thereto, whether frames bearing an address of the other of the MACs are forwardable thereto, and whether frames are directable to said local manager. 
     
     
       3. A two-port transparent bridge between a pair of LANs comprising separate means for connection to said LANs, separate parallel data path means for carrying data in mutually opposite directions in communication with said connection means and at least two separate processing means each in communication with a respective one of said data path means for forwarding frames of data only in respectively opposite directions from each of the LANs to the other via said data path means, and further including separate message discrimination means coupled to the LANs for receiving and discriminating messages from each of the LANs destined for a local manager. 
     
     
       4. A bridge as defined in claim 3 in which each of said separate message discrimination means is devoid of a programmable processor.